The digital micromirror device (DMD) is a micromechanical device, which may be used as a reflective spatial light modulator. It has an array of rotatable mirrors, fabricated over an address circuit having CMOS memory cells. A typical DMD has mirrors that are 16 micrometers wide on a pitch of 17 micrometers, and that rotate plus or minus 10 degrees from a flat (non-tilted) position.
When a DMD mirror rotates, it touches an underlying landing surface. During manufacture or during operation, mirrors of the DMD may become stuck to this landing surface. The sticking can occur in either direction of the mirror tilt, such that the mirror can be either stuck "off" or stuck "on".
One application of DMDs is image displays, where an array of mirror elements are individually addressed to form images. In such applications, a mirror element that is "off" is always perceived as a black pixel. A mirror element that is stuck "on" is always perceived as a pixel of maximum intensity.